Connection for continuous-current generators.



- I.. SCHON. CONNECTION FOR CONTINUOUS CURRENT GENERATORS.

APPLICATION FILED FEB. 3. I9I3.

Patented July 20,1915.

- drive.

WTTED TATJESE DATENT @FFTCE.

LUD'WIG SCHDN, 0F ESSEN-ON-THE-RUHR, GERMANY, ASSIGNOR T0 FRIED. KIRUPP AKTIENGESELLSCHAFT, OF ESSEN-ON-THE-RUHR, GERMANY.

CONNECTION FOB CONTINUOUS-CURRENT GENERATORS.

Specification of Letters Patent.

- Application filed February 3, 1918. Serial No. 746,024.

To all whom it may concern:

Be it known that I, Lunwie SCI-16X, residing at Essen-on-the-Ruhr, Germany, a subject of the Emperor of Germany, have in vented a certain new and useful Improve ment in Connections for Continuous-Current Generators, of which the following is a specification.

The subject matter of the present invention is a connection for continuous current generators, particularly intended for controlling d vnamos with Leonard-driving, which provides the advantage, that a very short time of eX'citat-ionand at the same time a very eflectivedestruction of the residual magnetism may be attained-in an extremely simple manner.

Two embodiments of the invention are illustrated in the accompanying drawing, where Figure 1 gives a diagrammatic representation of the connection and Fig. 2 a modified form of the connection.

' The connection shown in first described.

A. designates the rotor of a continuous current generator which is represented as a'controlling dynamo of a so called Leonard The rotor C of the corresponding continuous current motor is. by means of the conductor 13 connected with the clamps a and a of the rotor A, the field winding C of the formerrotor C being separately excited in well known manner. The generator is provided with a main field winding D and a compound winding E. The main field winding D is, on the other hand, by means ofa conductor F connected with that clamp g of a continuous current net work G, which has similar polarity with the clamp a Between the clamp g and the other clamp g of the net work G, is inserted a regulating resistance H, to which the rotor clamp a may be connected by means of a conductor F ending in a slidingcontact f so that eitherthe whole resistance H or only a part thereofis introduced into the circuit A, D, F, H, F or on the other hand the rotor A and the field winding D are short circuited through the conductor F and ii. In the first case, wherein the sliding contact f stands in direct connection with the clamp 9 the whole voltage formed by the net work G which constitutes the voltage source, is

Fig. 1 will be Patented July 20, 1915.

inserted into the circuit A, D, F, H, F By means of corresponding adjustment of the sliding contact f the inserted voltage may be diminished as required until the sliding contact 7' stands in direct connection with the clamp 9 when it will be equal to zero. As, in the state of permanence, the exciting voltage for the field winding D cannot ex. ceed the difference between the full net Work voltage and the highest value of the clamping voltage of the rotor A, the computation of the measurement of the field winding D should therefore naturally be based on this difference, which is considerably lower than ,the highest value of the clamping voltage of the generator rotor A. This circumstance possesses the advantage that the resistance of the field winding D, as well as the number of windings, and as a consequence also the self-induction willbe found comparatively small.

When the motor C C stands idle the slid ing contact f is in direct connection with the clamp g of the net work G. The rotor A and the field winding D are-also short circuited. In order to start the motor the sliding contact f is drawn in the direction of the arrow :0 until it reaches that position (as represented in the drawing), which corresponds to the desired number of revolutions of the motor. A fraction'of the net work voltage which corresponds to the position of the sliding contact f is now inserted in the circuit H, F, D, A, F, and there. will consequently arise a current therein, which will flow through the field winding D in the direction of the arrow shown on the drawing. As has already been mentioned, the field winding D only possesses comparatively low self-induction, the current attains very quickly its full strength; the time necessary for, the complete excitattpn of the generatouwill therefore be very s ort.

To stop the motor C C the circuit H F l) A F should be short eircuited by connecting the sliding contact f directly with the clamp 9 so that the voltage source G is disconnected. The rotor voltage which counter-acts the exciting current during the state of permanence further exist for a moment longer as a consequence of the selfinduction of the main field winding D and by the influence of the compound winding E, and it will generate a current in the short circuited circuit, which has the opposite direction to the exciting current produced in the state of permanence. In consequence of this a power field will be generated in the 'magnet frame of the generator by means of which the residual magnetism will be quickly and completely removed.

The embodiment of this invention illustrated in Fig. 2 difi'ers from the one described, only therein that the conductor F in said figure is not connected to the rotor clam a but instead to the intermediate brus a in the manner of the well known Sengel connection, so that in the circuit H F D A F always only a fraction, practically one half, of the rotor voltage generated through the induction action in the rotor, is opposed to the voltage existing between the clamp g and the sliding contact 7, and that therefore the half of the rotor I voltage heed'be smaller-than the net work voltage. The total rotor voltage may therefore be accepted as greater than the same in the first embodiment of the invention wherein it is always to be selected to be.

smaller than the net work voltage. The use of the Sengel connection possesses then a particular advantage as compared for instance with a voltage division throughthrottling of a rotorvoltage in a resistance cony nected in parallel to the rotor, whereby the counter-currenhacting to destroy the residual' magnetism, will be found considerably stronger durin the short circuiting of the main field win ing D.

Without changing the object of the invention, the field wlnding D and the conductor F may be connected to the rotor C of the motor instead of to the rotor A of the gen- Winding, and a source of external voltage,

said source being connected so as to act in opposition to the voltage of said armature; and means for adjusting the amount of external voltage to be inserted in the exciting circuit from naught to its maximum without interrupting the exciting circuit.

2. A continuous current generator having an exciting circuit containing in series the armature of the generator, a main field winding, and a source of external voltage,.

said source being connected so as to act in opposition to the voltage of said armature; and means tor ad ilsting the amount ofexternal voltage to be inserted in the exciting circuit from naught to its maximum with-,

out interrupting the exciting circuit; the part of the exciting circuit containingsaid main field winding and said source of external voltage being connected to two points of said armature, between which only a. fraction of the armature voltage is generated by induction. v

The foregoing specification signed at Barl lneli, Germany, this 13th day of January,

' nnnwie senor. MJ

In presence of- ALBERT Norma, Jnmns Fnsrnna. 

